According to Jesus in Matthew 5:1-16, the poor in spirit are blessed. In the message that Jesus preached on a mountainside, sometimes referred to as the Sermon on the Mount, he gives a series of statements known as the beatitudes, which begins with the phrase, “Blessed are the poor in spirit, for theirs is the kingdom of heaven.” (Matthew 5:3) Jesus makes use of a technique common in Hebrew literature that grows out of the parallelistic nature of Hebrew poetry, where instead of rhyming sounds, ideas are “rhymed” or repeated. The technique when it is used in narrative can be described as “newspaper style.” That is, just as a newspaper article will summarize its entire contents in the first paragraph, so in Hebrew, the first line of a narrative will often summarize what will then be expanded upon in the lines that follow. Thus, in his beatitudes, Jesus sets out to explain or define, in the lines that follow his opening statement, just who the “poor in spirit” might be, as well as giving some sense of the nature of “the kingdom of heaven.”
So who are “the poor in spirit?” The poor in spirit mourn, are meek, hunger and thirst for righteousness, are pure in heart, are peacemakers, and are persecuted. The first line, in verse 3 ends with the phrase “kingdom of heaven” and likewise, the last verse, verse 10, ends with the same phrase, tying the whole passage neatly together.
And what is the “kingdom of heaven?” The kingdom of heaven is described as a place where the poor in spirit are comforted, inherit the earth, are filled, shown mercy, see God, and are called the children of God.
On a side note, there is nowhere in the New Testament where Jesus describes the kingdom of heaven as being like the Roman Empire, or even like the Davidic kingdom. But of course that makes sense, given what Jesus says in Luke 17:20-21:
Once, on being asked by the Pharisees when the kingdom of God would come, Jesus replied, “The coming of the kingdom of God is not something that can be observed, nor will people say, ‘Here it is,’ or ‘There it is,’ because the kingdom of God is in within you.”